Vanadium oxides (VOx) have been highly paid attention to catalysts (Non-patent Document 1), elements for switching devices (Non-patent Document 2), antistatic coatings (Non-patent Document 3), thermosensors (Non-patent Document 4), cathodes of lithium ion battery (Non-patent Documents 5 and 6), counter-electrodes for electrochromic display devices (Non-patent Document 7) and the like.
In particular, vanadium oxides have the property of dramatically altering their optical and electrical characteristics by means of a semiconductor-metal phase transition from monoclinic crystals at low-temperature to tetragonal crystals at high-temperature during the transition temperature (transition temperature, Tt) (Non-patent Documents 8 and 9).
Since the transition temperature of vanadium oxide (VO2) is near 68° C., which is close to room temperature, it is expected as a promising material for thermoresponsive heat-shielding glass (smart windows) (Non-patent Documents 10 to 12), thermosensors (Non-patent Document 4), non-cooled infrared bolometers (non-cooled infrared detectors) (Non-patent Document 13), holographic storage systems (data recording media using materials with high photosensitive efficiency) (Non-patent Document 14), optical fiber switching devices (Non-patent Document 15), ultra-high-speed switching devices (Non-patent Document 16), photonic crystals (Non-patent Document 17) and the like.
Therefore, synthesis of vanadium oxides and related substances has been reported using various methods, including magnetron sputtering (Non-patent Documents 8, 18 and 19), electron beam deposition (Non-patent Documents 20 and 21), chemical vapor deposition method (Non-patent Documents 22 to 25), the sol-gel method (Non-patent Documents 2, 3, and 7), pulse laser deposition method (Non-patent Document 26) and the like.
Specifically, attention has focused on the potential of vanadium oxides (VOx) for catalysts, elements for switching device, antistatic coatings, thermosensors, lithium ion battery cathodes, electrochromic display device counter-electrodes and the like. In particular, vanadium oxides have the property of dramatically altering their optical and electrical characteristics by means of a semiconductor-metal phase transition from low-temperature monoclinic crystals to high-temperature tetragonal crystals at the transition temperature (transition temperature, Tt).
Since the transition temperature of vanadium oxide (VO2) is near 68° C., which is close to room temperature, it is expected as a promising material for thermoresponsive heat-shielding glass (smart windows), heat sensors, non-cooled infrared bolometers (non-cooled infrared detectors, holographic storage systems (data recording media using materials with high photosensitive efficiency), optical fiber switching devices, ultra-high-speed switching devices, photonic crystals and the like. Therefore, synthesis of vanadium oxides and related substances has been reported using various methods, including magnetron sputtering, electron beam deposition, chemical vapor deposition method, the sol-gel method, pulse laser deposition method and the like.
Recently, the aqueous solution process has gained attention from the standpoint of device construction on low-heat-resistance polymers and transparent conductive films. The aqueous solution process is also highly advantageous because it is an environmentally friendly process that uses little energy, produces little CO2 and does not require an organic binder for sintering purposes. For microfabrication of the thin film, a major consideration in the context of microdevice preparation is required.
However, the desirable properties of vanadium oxide are seriously affected by etching during micropatterning of the thin film. There is therefore a need for thin film micropatterning techniques that do not involve an etching process.
Problems of prior art with regard to vanadium oxides include the impossibility of coating on low-heat-resistance substrates, the difficulty of forming large areas, the difficulty of coating substrates with complex shapes, and the high equipment and manufacturing costs and the like. Microfabrication of the thin film is also a major consideration in the context of microdevice preparation. However, the desirable properties of vanadium oxides are seriously affected by etching during micropatterning of the thin film. Therefore, thin film micropatterning techniques need to be developed that do not involve an etching process. There is also increasing demand for a move towards environmentally friendly process that use less energy, produce less CO2 and do not require organic binders for sintering.    Non-patent Document 1: Zhu, Z. P.; Liu, Z. Y., Niu, H. X.; Liu, S. J.; Hu, T. D.; Liu, T.; Xie, Y. N., Journal of Catalysis 2001, 197(1), 6-16    Non-patent Document 2: Bullot, J.; Gallais, O.; Gauthier, M.; Livage, J., Applied Physics Letters 1980, 36(12), 986-988    Non-patent Document 3: Livage, J.; Beteille, F.; Roux, C.; Chatry, M.; Davidson, P., Acta Materialia 1998, 46(3), 743-750    Non-patent Document 4: Kim, B. J.; Lee, Y. W.; Chae, B. G., Yun, S. J.; Oh, S. Y.; Kim, H. T.; Lim, Y. S., Applied Physics Letters 2007, 90(2)    Non-patent Document 5: Schmitt, T.; Augustsson, A.; Nordgren, J.; Duda, L. C.; Howing, J.; Gustafsson, T.; Schwingenschlogl, U.; Eyert, V., Applied Physics Letters 2005, 86(6)    Non-patent Document 6: Munshi, M. Z. A.; Smyrl, W. H.; Schmidtke, C., Chemistry of Materials 1990, 2, (5), 530-534    Non-patent Document 7: Livage, J., Chemistry of Materials 1991, 3(4), 578-593    Non-patent Document 8: Shigesato, Y.; Enomoto, M.; Odaka, H., Japanese Journal of Applied Physics Part 1—Regular Papers Short Notes & Review Papers 2000, 39(10), 6016-6024    Non-patent Document 9: Imada, M.; Fujimori, A.; Tokura, Y., Reviews of Modern Physics 1998, 70(4), 1039-1263    Non-patent Document 10: Babulanam, S. M.; Eriksson, T. S.; Niklasson, G. A.; Granqvist, C. G., Solar Energy Materials 1987, 16(5), 347-363    Non-patent Document 11: Jorgenson, G. V.; Lee, J. C., Solar Energy Materials 1986, 14(3-5), 205-214    Non-patent Document 12: Manning, T. D.; Parkin, I. P., Journal of Materials Chemistry 2004, 14(16), 2554-2559    Non-patent Document 13: Jerominek, H.; Picard, F.; Vincent, D., Optical Engineering 1993, 32(9), 2092-2099    Non-patent Document 14: Bugayev, A. A., Gupta, M. C., Optics Letters 2003, 28(16), 1463-1465 Optical Fiber Switching Devices    Non-patent Document 15: Lee, C. E.; Atkins, R. A., Gibler, W. N.; Taylor, H. F., Applied Optics 1989, 28(21), 4511-4512    Non-patent Document 16: Cavalleri, A.; Toth, C.; Siders, C. W.; Squier, J. A.; Raksi, F.; Forget, P.; Kieffer, J. C., Physical Review Letters 2001, 87(23)    Non-patent Document 17: Xiao, D.; Kim, K. W.; Zavada, J. M., Journal of Applied Physics 2005, 97(10)    Non-patent Document 18: Kato, K.; Song, P. K.; Odaka, H.; Shigesato, Y., Japanese Journal of Applied Physics Part 1—Regular Papers Short Notes & Review Papers 2003, 42(10), 6523-6531    Non-patent Document 19: Theil, J. A.; Kusano, E.; Rockett, A., Thin Solid Films 1997, 298(1-2), 122-129    Non-patent Document 20: Ramana, C. V.; Hussain, O. M.; Naidu, B. S.; Reddy, P. J., Thin Solid Films 1997, 305(1-2), 219-226    Non-patent Document 21: Ramana, C. V.; Hussain, O. M., Advanced Materials for Optics and Electrons 1997, 7(5), 225-231    Non-patent Document 22: Manning, T. D.; Parkin, I. P.; Clark, R. J. H.; Sheel, D.; Pemble, M. E.; Vernadou, D., Journal of Materials Chemistry 2002, 12(10), 2936-2939    Non-patent Document 23: Manning, T. D.; Parkin, I. P.; Pemble, M. E.; Sheel, D.; Vernardou, D., Chemistry of Materials 2004, 16(4), 744-749    Non-patent Document 24: Sahana, M. B.; Shivashankar, S. A., Journal of Materials Research 2004, 19(10), 2859-2870    Non-patent Document 25: Barreca, D.; Armelao, L.; Caccavale, F.; Di Noto, V.; Gregori, A.; Rizzi, G. A.; Tondello, E., Chemistry of Materials 2000, 12(1), 98-103    Non-patent Document 26: Ramana, C. V.; Smith, R. J.; Hussain, O. M.; Chusuei, C. C.; Julien, C. M., Chemistry of Materials 2005, 17(5), 1213-1219